leetcode 有重复字符串的排列组合

1.题目要求:

2.题目代码：

class Solution {
public://运用回溯vector<string> result;string s;void backtricking(string S,vector<bool>& used){if(s.size() == S.size()){result.push_back(s);return;}for(int i = 0;i < S.size();i++){if(i > 0&&S[i] == S[i - 1]&&used[i - 1] == false){continue;}if(used[i] == false){used[i] = true;s.push_back(S[i]);backtricking(S,used);used[i] = false;s.pop_back();}}}vector<string> permutation(string S) {sort(S.begin(),S.end());vector<bool> used;used.resize(S.size(),false);backtricking(S,used);return result;}
};